Boiler



July 16, 1935. G, B WARREN 2,008,528

'BOILER Filed Sept. 3Q, 1955 Inventor-z Glenn B .War-ren,

His Attofneg.

Patented July 16, 1935 UNITED STATES BOILER Glenn B. Warren,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application September 30, 1933, Serial No. 691,689

3 Claims. (Cl. 122-250) The present invention relates to boilers forheating, evaporating and superheating a iluid such as water or mercury,more particularly to high pressure combustion boilers in which the fluidto be heated is forced through the heating elements and agpressure ofseveral atmospheres is maintained in the combustion space. Thecirculation of fluid through the heating elements in this type of boileris usually accomplished by the provision of pumps and the pressure inthe combustion space may be obtained by a compressor for forcing airinto the combustion space to maintain combustion therein, whichcompressor may be driven by a gas turbine receiving eX- haust gases fromthe boiler. The combustion gases are forced along the heating surfacesof the iluid containing elements at high velocity of the order ofseveral hundred feet per second. This naturally results in a high heattransfer and makes it necessary to provide forced circulation for thelluid to be heated in order to avoid excessive heating of the fluidconducting elements.

The output of a boiler of this type is several times larger than that ofan ordinary boiler with natural circulation and ilow of fluid andcombustion gases respectively.

The object of my invention is to provide an improved boiler of the typespecified which is simple in design and can be manufactured at low cost.

For a consideration of what I believe to be novel and my invention,attention is directed to the following description and the claimsappended thereto in connection with the accompanying I drawing.

In the single figure of the drawing I have shown a view partly insection of a boiler embodying my invention.

Broadly speaking, the boiler comprises two cylindrical double-walledbodies arranged in concentric spaced relation to define an annularspace. Located in this annular space and connected between the twobodies is a helically wound tube defining a spiral or helical path. Theinner body defines a combustion space which at one end receivescombustible material, such as oil together with air for maintainingcombustion and at theother end discharges combustion gases into thehelical path whence the gases after having passed along the helical pathare discharged into a stack or a gas turbine. Fluid to be evaporated andsuperheated is conducted to the inner body, then through the tubedelining the helical path, when it flows through the outer body to besuperheated and discharged. Each of the two bodies, as pointed outabove, has an inner and an outer Wall. These walls may be formed in anydesirable manner, such as by corrugated sheet metal or in a preferredconstruction by a tube or tubes.

Referring now more specifically to the rrangement illustrated in thedrawing, the two bodies and the means for conducting fluid from one bodyinto the other form a single tube receiving liquid at one end anddischarging elastic iluid at the other.

The inner body has an inlet conduit IIJ for receiving fluid to beheated. The tube forming the body is helically wound with adjacent turnsengaging each other. The engaging tube portions are united by fusedmetal vsuch as welds II or the like to render the space defined by theinner body gas-tight. The last turn I2 of the inner body is connected bya tube portion I3 to the inlet of a top layer of spirally wound tubeshaving an outlet I5 connected to a tube I6 helically wound about theinner body with adjacent turns spaced apart. The last turn I'I of thetube I6 is connected by a tube portion I8 to the first turn I9 of anouter cylindrical body. The turns of the outer cylindrical body engageeach other and the engaging portions are united by welds 20 or othermethods. The tube portion intermediate the outer and inner bodies arefastened either to the inner or the outer body. In the present instancethey are secured to the inner body by welds 2 I. The last turn 22 of theouter body is connected to a second top layer of tubes 23 Which end in aconduit 24 for discharging superheated elastic fluid. The inner layer,as well as the outer top layer of tubes, are united by welds 25 and 26.A cap 2l is welded to the discharge conduit 24 and the outer top layerof tubes to prevent leakage of gases. The two top layers of tubes andthe. cap 21 form in substance a cover or closing member for the outercylindrical body.

The heating elements are in the present instance previded in a casingcomprising a steel cylinder 28 concentrically spaced from the outerbody. A top plate 29 is fastened to flanges 30 of the cylinder 28 bymeans of bolts 3|. The cylinder is supported on a base plate 32 having acentral opening 33 for a burner 34. The outer body of tubes is supportedby the. cylinder by means of brackets or an annular ring 35 Welded onone side to the cylinder and on the other side to the lower turns of theouter body. The inner body is supported on an annular partition 36 whichis welded tothe base 32 and to the lower turn of the inner body. Theburner 34 is centrally arranged within the space defined by thepartition. An opening in the partition is connected to a conduit 31 forconducting compressed air into the combustion space. The lower end ofthe cylindrical steel body 28 has an opening connected to a conduit orstack 3'8 for discharging combustion gases.

During the operation the combustion gases formed in the combustion spaceof the inner bo'dy flow upward at high velocity and are forced throughan annular opening dened between the last turn of the inner body and theinner top layer into the helical path dened between the inner and outerbody. The velocity of the gases is considerably increased in saidhelical path. At the lower end of the helical path the combustion gasesare discharged into the conduit or stack 38. Liquid forced through inletIll into the lower end of the inner body flows through the turns formingthe inner body and under normal conditions is converted into vaporwithin the upper turns of the inner body. The conversion of liquid intovapor, however, may take place earlier or later depending upon operatingconditions. From the upper turn of the inner body the fluid flowsthrough connection I3 into the top layer I4, whence it flows throughtube portion I5 into the tube I6 forming the helical path in which tubethe liquid is normally superheated. From the end turn I1 of the lastmentioned tube the fluid flows through connecting tube I8 into the lowerturn of the outer body in which it is forced upward. From the last turn22 of the outer body the iluid flows through the outer top layer 23 intothe discharge conduit 24. Whereas I have shown the outer cylindricalbody as being enclosed in a steel casing, such steel casing may beomitted if desired.

One advantage of my improved boiler lies in its simplicity. A standardsize of this boiler may be constructed of standard tubes and anydesirable output may be obtained by providing a plurality of suchstandard size boiler units. The output per unit volume combustion spaceis Very high and comparatively little floor space is accordingly neededfor a boiler.

Having described the method of operation of my invention, together withthe apparatus which I now consider to represent the best embodimentthereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates:

1. In a single tube boiler, a helically wound tube with the walls ofadjacent turns united by fused metal to dene a gas tight combustionspace, means for conducting fuel and air at high pressure into thecombustion space, a second tube with thc walls of adjacent turns unitedby fused metal in concentric spaced relation to the ilrst tube. a thirdtube connected between the rst and the second tube being helically woundinto the space defined between the rst and second tubes in order to dcnca helical path for receiving at one end gases from the combustion space,and a stack connected to the other end of the helical path, thecombustion space having a large cross-section and being of a'volumesuillcient to cause complete combustion of fuel therein, the helicalpath being of considerable length but small cross-section as comparedwith the crosssection of the combustion space to cause the combustiongases to flow at high velocity therethrough.

2. In a high pressure combustion boiler, the combination of an innercylindrical body comprising a helically wound tube with adjacent turnsthereof engaging each other and being united along their entire lengthby fused metal to form a gas-tight 4combustion chamber, means forconducting fuel and air at high pressure into said chamber, thecombustion chamber having a large cross-section and a volume sufilcientto permit complete combustion of fuel therein, an outer cylindrical bodyconcentrically arranged with the inner body, the two bodies forming anannular space having a width equal to the diameter of one of said tubes,the outer body comprising a helically wound tube with adjacent turnsunited by fused metal, and a tube for conducting fluid to be heated andevaporated from the inner body to the outer body, said last named tubebeing helically wound into the annular space between the two bodies todefine a helical path for the gases discharged from the combustionspace, the helical path having a small cross-section as compared withthat of the combustion chamber to cause the combustion gases to flowthrough the helical path at high velocity.

3. In a boiler for heating and evaporating a fluid, two cylindricalbodies in concentric spaced relation, the inner body defining acombustion chamber, each body comprising a helically wound tube withadjacent turns of the tube engaging each other, a tube wound into thespace intermediate the bodies to define a helical path communicating atthe upper end with the combustion chamber, a portion of one of saidtubes forming a ceiling for thev combustion chamber, means forconducting fuel and air into the lower end of the combustion chamber,the cross-section of the helical path being a fraction of that of thecombustion chamber to cause a considerable increase l in velocity of thecombustion gases discharged at the upper end from the combustion chamberinto the helical path, and a conduit communicating with the lower end ofthe helical path for discharging combustion gases.

GLENN B. WARREN.

